A China News photo show Chinese police holding Vietnamese trafficked boys during a ceremony at border city Fangchenggang on May 3, waiting to return them to Vietnamese authorities

Chinese authorities on Friday handed over ten boys all under three-years-old, who had been trafficked into China in 2011 to representatives from Vietnam's Ministry of Public Security.

The babies were returned during a ceremony at the border city Fangchenggang in the Guangxi Zhuang autonomous region.

Colonel Pham Van Sy, head of the human trafficking and child crime department at the ministry, said the babies will be sent to local orphanages while police try to identify and locate their families, news website VnExpress reported.

Sy said Chinese authorities discovered the boys in July 2011 when they were between ten days and seven months old, sending them to social welfare centers in Guangxi province. Many had been taken into China by boat, while others were born there. It is not clear why it took nearly two years for the babies to be returned home.

China has arrested 43 suspects, including ten Vietnamese and has expanded its investigation into what they consider a major ring led by two Vietnamese trafficking boys into China from southern Vietnam.

Dat Viet newspaper cited Vietnamese police as saying two of the arrested Vietnamese have been identified as Binh and Thien Truc Bao Tran, mothers of two of thereturned babies. The women said they were unmarried and homeless, and had been brought to China to birth and sell their babies.

Trafficking women and children into China has been on the rise in recent years, fueled by China's one-child policy and its general preference for boys, according to sociologists.

A recent report by China Radio National said that since 2009, Chinese authorities have helped rescue more than 1,800 Vietnamese women and 41 Vietnamese children trafficked into China.

Vietnam police meanwhile have busted more than 3,000 human-trafficking attempts along its border with China since 2003, with around 1,200 would-be victims rescued in 2012 alone.